Hi! From the Tobu Nikko or JR Nikko Station, you can get there by bus or by taxi (or you can rent a car). For the bus, please note that in most cases, the bus will have no wheelchair access (from what I observed). Then, upon getting off at the nearest bus stop to Kammangauchi, you have to walk for 10+ minutes. The road here is concrete but not flat, BUT manageable by wheelchair. As you pass a local inn and park, the dirt road starts. If you take it slow, I think, its possible by wheelchair. You can go until the 1st line up of Jizo (the statues with the red bibs). Be mindful of other people around there because the road in front of the Jizo's is very narrow. BUT if you can go on a weekday or low season (like now!), there are usually no people milling around. After this, it would be difficult to move forward, because you have to climb a stone stairs. You will just miss the sort of hut that has a view of the river and the 2nd line up of Jizo's. Other than that, I think it's still worth a visit.